Microwave ovens have become a principle form of rapidly and effectively cooking and/or heating food products. Accordingly, the variety and type of food products available for preparation in microwave ovens is constantly increasing. Despite the convenience of heating offered by the microwave oven, the commercial success of many microwaveable food products has been limited by problems associated with heating such food products with microwave energy. For example, such problems are generally related to the quality of the food product and include overcooked portions, colds spots and burnt edges. Accordingly, there exists a continuing demand to improve the manner in which food products are heated in a microwave oven while decreasing the time required to heat the food products to an acceptable temperature.
Frequently, food products that are prepared for cooking or heating within a microwave oven are delivered to the consumers in containers that may be used directly within the microwave oven. These containers generally are intended to minimize problems typically associated with the microwaving of food products by attempting to more uniformly heat the food products.
A variety of prior art packages and containers have attempted to provide improved heating uniformity, modified power absorption, and selective heating. One common technique known in the art is to provide packages with a shielding technology to promote a more uniform heating within the food product. For example, a microwave-reflective material is often used to shield the microwave energy and redistribute the energy. Accordingly, various prior art containers utilize microwave-reflective material to shield and redistribute energy within the food product. Generally, the microwave-reflective material is positioned within the tray to define areas which completely reflect the microwave energy and areas which are completely transparent to the microwave energy. For example, U.S. Pat. No. 4,351,997 to Mattison et al., incorporated in its entirety by reference herein, discloses a container whose peripheral wall and rim is covered with a microwave-reflective material. The bottom of the tray, however, is essentially free of microwave-reflective material and thus provides an area which is essentially microwave-transparent. Additional containers which utilize microwave-reflective technology with the use of microwave-reflective material are disclosed in U.S. Pat. No. 5,117,078 to Beckett; U.S. Pat. No. 4,626,641 to Brown; U.S. Pat. No. 5,416,304 to De La Cruz; and U.S. Pat. No. 6,102,284 to Lafferty et al., each of whose disclosure is incorporated by reference herein.
While the microwave-reflective material is satisfactory in moderating the microwave energy of the food product within the container, the microwave-reflective material, in reflecting radiation away from the food product, may increase the cooking or heating time of the food product. Additionally, such techniques to moderate microwave energy may detrimentally impact the quality of the heated food product, such as, excessive moisture loss or the like. There thus remains a need for an efficient and economic container capable of providing for a more uniform heating of the food product therein, decreasing the required cook time and enhancing food product characteristics.